Biology subjects

Kazmirczak, F.

Publications and source records attributed to Kazmirczak, F..

5 recordsLinked to original sources

bioRxiv2023

Ketone bodies in Right Ventricular Failure: A Unique Therapeutic Opportunity

Introductory ParagraphKetone bodies are pleotropic metabolites that play important roles in multiple biological processes ranging from bioenergetics to inflammation regulation via suppression of the NLRP3 inflammasome, and epigenetic modifications. Ketone bodies are elevated in left ventricular failure (LVF) and multiple approaches that increase ketone concentrations exert advantageous cardiac effects in rodents and humans. However, the relationships between ketone bodies and right ventricular failure (RVF) are relatively unexplored. Moreover, the cardioprotective properties of ketones in preclinical RVF are unknown. Here, we show a compensatory ketosis is absent in pulmonary arterial hypertension (PAH) patients with RVF. In the monocrotaline (MCT) rat model of PAH-mediated RVF, a dietary-induced ketosis improves RV function, suppresses NLRP3 inflammasome activation, and combats RV fibrosis. The summation of these data suggest ketogenic therapies may be particularly efficacious in RVF, and therefore future studies evaluating ketogenic interventions in human RVF are warranted.

biochemistry↗

bioRxiv2023

Junctophilin-2 Regulates Mitochondrial Metabolism

Right ventricular dysfunction (RVD) is a risk factor for mortality in multiple cardiovascular diseases, but approaches to combat RVD are lacking. Therapies used for left heart failure are largely ineffective in RVD, and thus the identification of molecules that augment RV function could improve outcomes in a wide-array of cardiac limitations. Junctophilin-2 (JPH2) is an essential protein that plays important roles in cardiomyocytes, including calcium handling/maintenance of t-tubule structure and gene transcription. Additionally, JPH2 may regulate mitochondrial function as Jph2 knockout mice exhibit cardiomyocyte mitochondrial swelling and cristae derangements. Moreover, JPH2 knockdown in embryonic stem cell-derived cardiomyocytes induces downregulation of the mitochondrial protein mitofusin-2 (MFN2), which disrupts mitochondrial cristae structure and transmembrane potential. Impaired mitochondrial metabolism drives RVD, and here we evaluated the mitochondrial role of JPH2. We showed JPH2 directly interacts with MFN2, ablation of JPH2 suppresses mitochondrial biogenesis, oxidative capacity, and impairs lipid handling in iPSC-CM. Gene therapy with AAV9-JPH2 corrects RV mitochondrial morphological defects, mitochondrial fatty acid metabolism enzyme regulation, and restores the RV lipidomic signature in the monocrotaline rat model of RVD. Finally, AAV-JPH2 improves RV function without altering PAH severity, showing JPH2 provides an inotropic effect to the dysfunction RV.

physiology↗

bioRxiv2023

A Multi-omic and Multi-Species Analysis of Right Ventricular Failure

Right ventricular failure (RVF) is a leading cause of morbidity and mortality in multiple cardiovascular diseases, but there are no approved treatments for RVF as therapeutic targets are not clearly defined. Contemporary transcriptomic/proteomic evaluations of RVF are predominately conducted in small animal studies, and data from large animal models are sparse. Moreover, a comparison of the molecular mediators of RVF across species is lacking. Here, we used transcriptomics and proteomics analyses to define the molecular pathways associated with cardiac MRI-derived values of RV hypertrophy, dilation, and dysfunction in pulmonary artery banded (PAB) piglets. Publicly available data from rat monocrotaline-induced RVF and pulmonary arterial hypertension patients with preserved or impaired RV function were used to compare the three species. Transcriptomic and proteomic analyses identified multiple pathways that were associated with RV dysfunction and remodeling in PAB pigs. Surprisingly, disruptions in fatty acid oxidation (FAO) and electron transport chain (ETC) proteins were different across the three species. FAO and ETC proteins and transcripts were mostly downregulated in rats, but were predominately upregulated in PAB pigs, which more closely matched the human data. Thus, the pig PAB metabolic molecular signature was more similar to human RVF than rodents. These data suggest there may be divergent molecular responses of RVF across species, and that pigs more accurately recapitulate the metabolic aspects of human RVF.

biochemistry↗

bioRxiv2023

Ferroptosis Promotes Pulmonary Hypertension

BackgroundMitochondrial dysfunction, characterized by impaired lipid metabolism and heightened reactive oxygen species (ROS) generation, results in lipid peroxidation and ferroptosis. Ferroptosis is an inflammatory mode of cell death that promotes complement activation and macrophage recruitment. In pulmonary arterial hypertension (PAH), pulmonary arterial endothelial cells (PAEC) exhibit cellular phenotypes that promote ferroptosis. Moreover, there is ectopic complement deposition and inflammatory macrophage accumulation in the pulmonary vasculature. However, the effects of ferroptosis inhibition on these pathogenic mechanisms and the cellular landscape of the pulmonary vasculature are incompletely defined. MethodsMulti-omics and physiological analyses evaluated how ferroptosis inhibition modulated preclinical PAH. The impact of AAV1-mediated expression of the pro-ferroptotic protein ACSL4 on PAH was determined, and a genetic association study in humans further probed the relationship between ferroptosis and pulmonary hypertension (PH). ResultsFerrostatin-1, a small-molecule ferroptosis inhibitor, mitigated PAH severity in monocrotaline rats. RNA-seq and proteomics analyses demonstrated ferroptosis was associated with PAH severity. RNA-seq, proteomics, and confocal microscopy revealed complement activation and pro-inflammatory cytokines/chemokines were suppressed by ferrostatin-1. Additionally, ferrostatin-1 combatted changes in endothelial, smooth muscle, and interstitial macrophage abundance and gene activation patterns as revealed by deconvolution RNA-seq. Ferroptotic PAEC damage associated molecular patterns restructured the transcriptomic signature, mitochondrial morphology, and promoted proliferation of pulmonary artery smooth muscle cells, and created a pro-inflammatory phenotype in monocytes in vitro. AAV1-Acsl4 induced an inflammatory PAH phenotype in rats. Finally, single-nucleotide polymorphisms in six ferroptosis genes identified a potential link between ferroptosis and PH severity in the Vanderbilt BioVU repository. ConclusionsFerroptosis promotes PAH through metabolic and inflammatory mechanisms in the pulmonary vasculature.

biochemistry↗

bioRxiv2022

Intermittent Fasting Activates AMP-Kinase to Restructure Right Ventricular Lipid Metabolism and Microtubules in Rodent Pulmonary Arterial Hypertension

Intermittent fasting (IF) extends lifespan via pleotropic mechanisms, but one important molecular mediator of the beneficial effects of IF is AMP-kinase (AMPK). AMPK enhances lipid metabolism and modulates microtubule dynamics. Dysregulation of these two molecular pathways causes right ventricular (RV) failure in pulmonary arterial hypertension (PAH). In two models of rodent PAH, we show IF activates RV AMPK, which restores mitochondrial morphology and peroxisomal density and restructures mitochondrial/peroxisomal lipid metabolism protein regulation. IF also increases electron transport chain (ETC) protein abundance and activity in the RV. Echocardiographic and hemodynamic measures of RV function are positively associated with fatty acid oxidation and ETC protein levels in correlational heatmapping analyses. IF also combats heightened microtubule density, which normalizes t-tubule structure. In summation, we demonstrate IF-mediated AMPK signaling counteracts two key molecular drivers of RV failure. Thus, IF may be a novel treatment approach for RV dysfunction, a currently untreatable and lethal consequence of PAH. Highlights- Intermittent fasting activates AMPK to restructure right ventricular mitochondrial and peroxisomal fatty acid fatty acid metabolism in two rodent models of PAH. - Intermittent fasting prevents downregulation of multiple electron transport chain proteins in both monocrotaline and Sugen-hypoxia RVs. - Pathological microtubule-mediated junctophilin-2 dysregulation and subsequent t-tubule remodeling is mitigated by intermittent fasting. - Intermittent fasting suppresses the induction of both the canonical and peroxisomal ferroptosis pathways in RV failure.

biochemistry↗